1. Field of the Invention
The present invention relates generally to asynchronous transfer mode (ATM) switching systems, and more specifically to an ATM self-routing switching system of the input buffer type.
2. Description of the Related Art
Batcher-Banyan network topology is well known in the ATM switching art. The Batcher network is a sorting network that precedes Banyan network to provide shuffling of cells destined to the same outlet. Another technique for resolving contention involves the use of a scheduling circuit that comprises comparators. Also known is an arbitration network proposed in a Japanese-language paper "Evaluation of the Experimental ATM Switching System", K. Hayashi et al, Institute of Electronics, Information and Communications of Japan, (SSE88-171).
However, the known techniques need complex contention detection circuitry where logic circuits are connected in multiple stages, delays are involved to detect contentions. A further shortcoming of the prior techniques is that priority is given in a fixed pattern, and hence, it is impossible to give priority impartially to all cells and adaptively in response to changing contention status.